1. Field of the Invention
This invention relates generally to memory cards with signal processing elements thereon; and more particularly to memory SIMMs or DIMMs having signal processing elements thereon to receive data from selected addresses and perform operations thereon when the memory bus is not available to the signal processing element.
2. Background Information
The use of signal processing elements, especially digital signal processing elements (DSPs), is being proposed as components on memory cards and boards for use in computers. The purpose is to allow the DSP to use some portion of the memory while that memory is not being utilized by the system. This provides significant cost savings by making a potentially large block of memory available to the DSP without adding a totally separate system memory bus and extra memory for the DSP. This results in more computing power at a lower cost. However, conventionally, the DSP has access to the memory only when the system does not have control of the memory bus for the idle capacity. This leaves the DSP unoccupied and, thus, under utilized for significant periods of time.
According to the present invention, a memory card having a memory bus controller is provided, which card has a signal processing element, preferably a digital signal processor (DSP) thereon. The card is used in a computer system as add-on memory. Also, a method of using such a card in a computer system is provided. The memory bus controller and the signal processing element are programmed to pass all the addresses in the memory on the card and the associated data received from the CPU to the signal processing element where they are stored in memory. The signal processing element is programmed to perform selected operations on the addresses and data irrespective of whether the signal processing element has control of the system bus. These operations can include keeping track of read/write operations and the locations of these operations. This information can be easily accessed by the computer system and used for memory optimization.
The DSP can also xe2x80x9csnoopxe2x80x9d the memory bus when it is unavailable to the control of the DSP, i.e. when the system has control of the memory bus. The memory bus controller passes addresses and data to the DSP as it is received, when the DSP receives addresses that are in its normal or regular range, or other selected ranges, for processing in the memory. The DSP can capture the data and do xe2x80x9cearlyxe2x80x9d processing or preprocessing of this information before the DSP gains control of the memory.